If you budget allows then you might want to check out the JetQuay service which provides a unique Changi experience from plane door to hotel via private terminal and controls etc. Not cheap but worth every penny. Your hotel will probably organise it for you.
An overview is
here
Funny, I was thinking about booking the Quayside service, but $250SGD is pretty steep imo for max. 15min of service.
I sent the hotel an e-mail inquiring whether they offer any package (i.e. limousine + Quayside service for a decent price), some hotels also offer this as a complimentary service, letīs see.
The Jetside service looks like great fun, but seriously, Iīd never spend $1500SGD/US$1000 for a 5min drive even if I had that kind of money.
May I ask which of the three services you used and why you think it was worth the money?